KR100590260B1 - Organic Electro Luminescence Display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device having a uniform color coordinate by controlling a thickness of a SiNx film under an organic light emitting device. The present invention relates to an active layer having a source / drain region and a gate insulating film. A TFT having a formed gate electrode and a source / drain electrode electrically connected to the source / drain region through a contact hole of an interlayer insulating film; A protective film formed on the insulating substrate including the TFT and having a via hole exposing any one of the source / drain electrodes; And an organic light emitting element electrically connected to any one of the source / drain electrodes through the via hole, wherein the passivation layer provides an organic light emitting display device having a thickness variation range of 200 μs or less.

Organic electroluminescent display, protective film, SiNx, color coordinate, emission spectrum

Description

Organic Electroluminescent Display

1 is a cross-sectional view illustrating an organic light emitting display device according to a preferred embodiment of the present invention.

2 is a view for explaining the color coordinate uniformity of a red organic light-emitting device according to the thickness change of the protective film made of SiNx having a low light transmittance.

3A to 3C are diagrams for explaining spectral waveform uniformity of an organic light emitting display device according to a film thickness variation range made of SiNx having a low light transmittance.

4A and 4B are views for explaining a change in the spectral waveform of light emitted from a blue light emitting organic electroluminescent display with respect to the thickness change of a film made of SiNx.

(Explanation of symbols for main parts of drawing)

100; Insulating substrate 110; Buffer layer

120; Active layer 130; Gate insulating film

140; Gate electrode 150; Interlayer insulation film

161, 165; Source / drain electrodes 170; Shield

180; Interlayer insulating film 190; Organic light emitting device

191; The pixel electrode 192; Pixel Definition Film

193; An organic light emitting layer 194; Upper electrode

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device having a uniform color coordinate by adjusting a thickness of a SiNx film under an organic light emitting device.

In general, an organic light emitting display device injects electrons and holes into an emission layer from an electron injection electrode and a hole injection electrode, respectively, to form an injected electron ( A light emitting display device that emits light when an exciton in which electrons and holes are combined falls from an excited state to a ground state.

Due to this principle, unlike a conventional thin film liquid crystal display device, since a separate light source is not required, there is an advantage of reducing the volume and weight of the device.

A method of driving the organic light emitting display device may be divided into a passive matrix type and an active matrix type.

The passive matrix type organic light emitting display device has a simple structure and a simple manufacturing method. However, the passive matrix type organic light emitting display device has a high power consumption and a large area of the display device, and the opening ratio decreases as the number of wirings increases.

Therefore, the pass matrix organic electroluminescent display device is used when applied to a small display element, whereas the active matrix organic electroluminescent display device is used when applied to a large area display device.

The active matrix organic light emitting display device uses SiNx as an insulating film. In particular, after forming the thin film transistor for driving the organic light emitting device, a protective film made of SiNx is introduced to improve the characteristics of the thin film transistor through the protection and heat treatment process of the thin film transistor.

However, the film made of SiNx has a low light transmittance and is generally formed by a method such as CVD, and thus has a large thickness variation. Therefore, the color coordinates of the organic electroluminescent display and the spectral waveform of light emitted from the organic electroluminescent display are reduced. Uneven problem occurs.

An object of the present invention is to solve the above problems of the prior art, the present invention is formed on an insulating substrate, the active layer having a source / drain region, a gate electrode formed on the gate insulating film, contact holes of the interlayer insulating film A TFT having a source / drain electrode electrically connected to the source / drain region through the TFT; A protective film formed on the insulating substrate including the TFT and having a via hole exposing any one of the source / drain electrodes; And an organic light emitting diode electrically connected to any one of the source / drain electrodes through the via hole, wherein the passivation layer provides an organic light emitting display device having a thickness variation range of 200 μs or less.

More preferably, the protective film is made of SiNx, and the thickness variation range of the protective film is preferably 100 kPa or less.

It is preferable to further include a buffer layer made of SiNx on the insulating substrate and having a thickness variation range of 200 μs or less, more preferably the buffer layer made of SiNx, and preferably having a thickness variation range of 100 μs or less.

In addition, the present invention is formed on an insulating substrate, a source / drain electrode electrically connected to the source / drain region through an active layer having a source / drain region, a gate electrode formed on the gate insulating layer, and a contact hole of an interlayer insulating layer. A TFT having a; A protective film formed on the insulating substrate including the TFT and having a via hole exposing any one of the source / drain electrodes; And an organic light emitting element electrically connected to any one of the source / drain electrodes through the via hole, wherein at least one of the gate insulating film, the interlayer insulating film, and the protective film is made of SiNx, and the film made of SiNx has a thickness variation. It is characterized by providing an organic light emitting display device having a range of 200 mW or less.

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Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a cross-sectional view illustrating an organic light emitting display device according to an exemplary embodiment of the present invention.

The organic light emitting display device according to the exemplary embodiment of the present invention has a structure in which light emission efficiency is improved by removing a material having a low light transmittance in a light emitting area.

Referring to FIG. 1, a buffer layer (diffusion barrier) 110 is formed to prevent impurities such as metal ions from diffusing into the active layer (polycrystalline silicon) from the insulating substrate 100 on the insulating substrate 100. Deposition is by means of PECVD, LPCVD, sputtering, and the like.

After the buffer layer 110 is formed, an amorphous Si film is deposited on the buffer layer 110 using a method such as PECVD, LPCVD, or sputtering. And a dehydrogenation process is performed in a vacuum furnace. When the amorphous silicon film is deposited by LPCVD or sputtering, it may not be dehydrogenated.

The amorphous silicon is crystallized through a crystallization process of amorphous silicon that irradiates the amorphous silicon film with high energy to form a polycrystalline silicon film (poly-Si). Preferably, a crystallization process such as ELA, MIC, MILC, SLS, SPC is used as the crystallization process.

After the polycrystalline silicon film is formed, a photoresist for forming an active layer is formed on the polycrystalline silicon film, and the active layer 120 is formed by patterning the polycrystalline silicon film using the photoresist as a mask.

A gate insulating layer 130 is deposited on the active layer 120, a gate metal is deposited on the gate insulating layer 130, and the gate metal is patterned to form a gate electrode 140.

After forming the gate electrode 140, source / drain regions 121 and 125 are formed by doping an impurity having a predetermined conductivity in the active layer 120 using the gate electrode 140 as a mask. A region between the source / drain regions 121 and 125 in the active layer serves as a channel region 123 of the TFT.

After the source / drain regions 121 and 125 are formed by doping impurities into the active layer 120, an interlayer insulating layer 150 is formed over the entire insulating substrate 100, and then patterned to form the source / drain regions 121. Contact holes 151 and 155 exposing a portion of the contact hole 125.

Then, a predetermined conductive film is deposited on the entire surface of the insulating substrate 100, and photo-etched to form a source / drain electrically connected to the source / drain regions 121 and 225 and the contact holes 151 and 255. Electrodes 161 and 165 are formed.

After forming the source / drain electrodes 161 and 165, a passivation layer 170 is formed on the entire surface of the insulating substrate 100.

At this time, the protective film 170 is made of SiNx, it is preferable that the thickness variation range of the protective film 170 is 200 Å or less, more preferably the protective film 170 is 100 Å or less thickness variation range. This is because as the thickness variation range of the passivation layer 170 made of SiNx increases, the uniformity of color coordinates and spectral waveforms of light emitted from the organic light emitting element to be formed later decreases.

After the inorganic protective film 170 is formed, heat treatment is performed. The heat treatment is to cure damage generated in the TFT manufacturing process to improve characteristics of the thin film transistor.

After the heat treatment, the planarization film 280 may be formed to remove the step difference of the lower structure. In this case, as the planarization layer 180, it is preferable to use a material that can smooth the TFT's curvature because it has fluidity such as acryl, polyimide (PI), polyamide (PA), or benzocyclobutene (BCB). Do.

After the planarization layer 180 is formed, a via hole 185 exposing one of the source / drain electrodes 161 and 165, for example, a portion of the drain electrode 165, is formed.

Next, an organic light emitting device 190 is formed to be electrically connected to the drain electrode 175 through the via hole 185.

In this case, the organic light emitting device 190 includes a pixel electrode 191, a pixel defining layer 192 having an opening exposing a portion of the pixel electrode 191, an organic light emitting layer 193 formed on the opening, and the insulation. The upper electrode 194 is formed on the entire surface of the substrate 100.

In addition, the organic light emitting layer 193 may be composed of several layers according to its function. In general, the organic light emitting layer 193 may include a light emitting layer, an hole injection layer HIL, a hole transport layer HTL, and a hole blocking layer HBL. ), An electron transport layer (ETL), and an electron injection layer (EIL).

Although not shown in the drawings, the organic light emitting device 190 is encapsulated using an upper substrate.

2 is a view for explaining the color coordinate uniformity of the red organic light emitting diode according to the thickness change of the protective film made of SiNx having a low light transmittance.

Referring to FIG. 2, it can be seen that, in the red organic light emitting device, the change in the color coordinates is smaller in the case where the thickness variation range of the film made of SiNx is 100 ms than in the case where the thickness variation range of the film made of SiNx is 200 ms and 600 ms.

That is, in the case of the red organic light emitting device, it is understood that the smaller the thickness variation range of the film made of SiNx, the better the uniformity of the color coordinates of the light emitted from the organic light emitting device.

3A to 3C are diagrams for explaining the spectral waveform uniformity of the organic electroluminescent display device according to the film thickness deviation range made of SiNx having a low light transmittance, and FIG. 3A is a thickness of 6000 μs and a thickness deviation range of 600 μs. FIG. 3B is a diagram illustrating uniformity of the spectral waveform in the case of FIG. 3B, and FIG. 3B is a diagram illustrating the uniformity of the spectral waveform in the case where the film thickness of SiNx is 1000 ms and the thickness deviation range is 100 ms. It is a figure explaining the uniformity of the spectral waveform in the case of 200 Hz deviation range.

3A to 3C, it can be seen that the uniformity of the spectral waveform of the light emitted from the organic electroluminescent display is excellent when the thickness uniformity of the film made of SiNx is 200 μs or less, and the uniformity of the spectral waveform is poor above that. . In particular, when the thickness variation range of the film made of SiNx is 600 kV, the uniformity of the spectral waveform of the light emitted from the organic electroluminescent display is very poor.

That is, when the thickness variation range of the film made of SiNx is 200 kV, the spectral waveform of the light emitted from the organic electroluminescent display is more uniform than when the thickness variation range of the film made of SiNx is 600 kV, and the thickness variation range of the film made of SiNx is 100 kV. It can be seen that the spectral waveform of the light emitted from the organic electroluminescent display is more uniform than the case where the thickness variation range of the film made of SiNx is 200 kPa.

Therefore, it can be seen that the smaller the thickness variation range of the film made of SiNx, the more uniform the spectral waveform of the light emitted from the organic light emitting display device.

4A and 4B are diagrams for explaining changes in spectral waveforms of light emitted from a blue light emitting organic electroluminescence display with respect to a thickness change of a film made of SiNx.

Referring to Figs. 4A and 4B, when the thickness of the film made of SiNx is ± 100 GPa when the thickness of the film made of SiNx is based on the spectral waveform when the thickness is 6000 mV, the change in the spectral waveform is small. However, when the change in the thickness of the film made of SiNx is ± 300 Hz, the change in the spectral waveform is large.

That is, it can be seen that the spectral waveform changes as the thickness difference of the film made of SiNx increases.

In the organic electroluminescent display device as described above, it can be seen that the smaller the thickness variation range of the film made of SiNx, the more uniform the color coordinates and the emission spectrum waveform are.

In the above description, a protective film is described as an example of a film made of SiNx. However, even when a film made of SiNx is formed in the buffer layer, the gate insulating film, or the interlayer insulating film under the organic light emitting element, the thickness variation of the film made of SiNx is controlled. The uniformity of the color coordinates and the emission spectrum of the electroluminescent element can be obtained.

As described above, according to the present invention, an organic electroluminescent display device having a uniform color coordinate and emission spectrum can be provided by adjusting the thickness variation of a film formed of SiNx under the organic light emitting element.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (10)

A TFT formed on the insulating substrate and having an active layer having a source / drain region, a gate electrode formed on the gate insulating film, and a source / drain electrode electrically connected to the source / drain region through a contact hole of the interlayer insulating film; ; A protective film formed on the insulating substrate including the TFT and having a via hole exposing any one of the source / drain electrodes; An organic light emitting diode electrically connected to any one of the source / drain electrodes through the via hole; And the passivation layer has a thickness variation range of 200 mW or less. The method of claim 1, And the passivation layer is formed of SiNx. The method of claim 1, And the passivation layer has a thickness variation range of 100 kΩ or less. The method of claim 1, And a buffer layer formed of SiNx on the insulating substrate and having a thickness variation range of 200 mW or less. The method of claim 4, wherein And the buffer layer has a thickness variation range of 100 kΩ or less. A TFT formed on the insulating substrate and having an active layer having a source / drain region, a gate electrode formed on the gate insulating film, and a source / drain electrode electrically connected to the source / drain region through a contact hole of the interlayer insulating film; ; A protective film formed on the insulating substrate including the TFT and having a via hole exposing any one of the source / drain electrodes; An organic light emitting diode electrically connected to any one of the source / drain electrodes through the via hole; And at least one of the gate insulating film, the interlayer insulating film, and the protective film is made of SiNx, and the film made of SiNx has a thickness variation range of 200 mW or less. delete The method of claim 6, The film made of SiNx has a thickness variation range of 100 kPa or less. The method of claim 6, And a buffer layer formed of SiNx on the insulating substrate and having a thickness variation range of 200 mW or less. The method of claim 9, And the buffer layer has a thickness variation range of 100 kΩ or less.

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